Many-body theory for positronium-atom interactions

TL;DR

This paper develops a many-body-theory approach to study positronium-atom interactions, successfully calculating scattering cross sections and annihilation rates that agree with previous theoretical and experimental data.

Contribution

It introduces a new many-body-theory framework for positronium-atom interactions and provides first calculations of scattering and annihilation rates for He and Ne.

Findings

Cross sections for He match previous calculations.

Momentum-transfer cross section for Ne agrees with experiments.

Annihilation rates $^1Z_\text{eff}$ match measured values.

Abstract

A many-body-theory approach has been developed to study positronium-atom interactions. As first applications, we calculate the elastic scattering and momentum-transfer cross sections and the pickoff annihilation rate $^1Z_\text{eff}$ for Ps collisions with He and Ne. The cross section for He is in agreement with previous coupled-state calculations, and the momentum-transfer cross section for Ne agrees with available experimental data. $^1Z_\text{eff}$ is found to be 0.13 and 0.26 for He and Ne, respectively, in excellent agreement with the measured values.